Corporate lobbying and donations to both parties are a direct product of the growth of government regulation, interference in industries, bailouts, grants and other forms of corporate welfare
It is part of the basic theory of government that when the regulators try to regulate the regulated, the regulated will in turn try to control the terms of their regulation by attempting to influence the regulators. In other words, that which government controls, will try to control it. Because regulation is a two way street. By regulating people, countries and industries-- you are entering into a relationship with that which you regulate.